Name: DOUGLAS GOMES VIANA

Publication date: 01/02/2018
Advisor:

Name	Role
FÁBIO RIBEIRO PIRES	Advisor *
ROBSON BONOMO	Co-advisor *

Examining board:

Name	Role
ADRIANO ALVES FERNANDES	Internal Alternate *
ELISA MITSUKO AOYAMA	External Alternate *
FÁBIO RIBEIRO PIRES	Advisor *
ROBSON BONOMO	Co advisor *

Summary: VIANA, Douglas Gomes; M.Sc.; Universidade Federal do Espírito Santo; Fevereiro de 2018; Macrophyte density: strategy to enhance the phytoremediation of barium in a field flooded environment; Adviser: Fábio Ribeiro Pires. Co-advisors: Robson Bonomo; Fernando Barboza Egreja Filho. Heavy metals have been the subject of much research in recent decades due to their accumulation in organisms and the environment. The Ba has been widely used in oil drilling fluids in the form of barite (BaSO4), which due to its low solubility, has a low degree of toxicity, however, under anaerobic conditions promoted by flooding, sulfate is reduced to sulfide and the barium that can be released to soil solution, posing a risk to humans and plants. Knowing this, a field study was conducted in Brazil from April 2016 to February 2017 in an area with a history of accidental contamination by Ba, which remains submerged for most of the year. The phytoremediation species Typha domingensis (T) and Eleocharis acutangula (E) were cultivated in a consortium at four plant densities (4-32, 8-64, 12-128 and 16-256 plants T-E m-2). The total mass of Ba extracted was higher for the density of 4-32 plants m-2, accumulating in the aerial part (≈ 450 g Ba ha-1) and root (≈ 500 g Ba ha-1). Ba soil content in the 0.0-0.2 m layer at the end of 300 days decreased by 75.78% (4-32 plants m-2), 42.09% (16-256 plants m-2), 34.43% (8-64 plants m-2) and did not present reduction to density of 12-128 plants m-2. For the 0.2-0.4 m layer the concentrations were not reduced. Therefore, a density of 4-32 plants m-2 is indicated for presenting high levels of Ba in the plant tissue, promoting this way a greater reduction of soil barium.

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